Polymers, particularly segmented copolymers of polytetrahydrofurans (usually as the diols) and polyesters or poly(urea-urethanes) are commonly used in commercial products, such as thermoplastic elastomers (Hytrel.RTM. thermoplastic elastomer), spandex fibers (Lycra.RTM. spandex fiber) and urethane rubbers (Adiprene.RTM. urethane rubber). The usual procedure in making these products is to combine a polyether diol with suitable reactants, such as ester segment forming compounds, or urea and/or urethane forming compounds such as amines and/or diols with diisocyanates. Improved methods of making such commercially important polymers are sought by the artisan. Polyether oligomer diols are important "monomeric" intermediates in many polymers, such as polyurethanes.
U.S. Pat. No. 3,842,019 describes the polymerization of oxiranes and other small ring compounds by a presumed cationic mechanism, using as the catalyst the decomposition products of metal perfluoroalkylsulfonates. These catalysts are described as "latent", that is no reaction occurs until the metal salt is decomposed. The reactions reported are relatively slow, even at elevated temperatures.
U.S. Pat. Nos. 5,084,586 and 5,124,417 describe the cationic polymerization of various monomers, including cyclic ethers, using onium cations, whose corresponding anions are fluororalkylsulfatometallates. Onium ion catalyzed cationic polymerizations are well known, and there is no mention in these patents of the use of metal salts not containing onium ions, such as metal triflates, as catalysts for the polymerization of cyclic ethers.
J. S. Hrkach, et al., Macromolecules, vol. 23, p. 4042-4046 (1990) describe the polymerization of tetrahydrofuran using trimethylsilyl trifluoromethanesulfonate as the initiator. No mention is made of any other triflates as catalysts for this polymerization.
G. A. Olah, et al., J. Appl. Polym. Sci., Vol. 45, 1355-1360 (1992) describe the use of boron, aluminum and gallium tristriflate to catalyze the polymerization of THF.